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@eonist
Created March 12, 2026 20:26
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frame-build.md

That's a smart move. The Detroit is the spiritual reference, but the Omera needs its own visual identity. A seat tube cutout is a strong signature — instantly recognizable and signals "this is a track-bred frame" without copying Dosnoventa's exact look.

What Makes Omera Visually Distinct from Detroit

Feature Detroit Omera
Seat tube Standard round Cutout wrapping rear wheel
Down tube Columbus Airplane ovalized 50mm round (battery inside)
Drive Chain Gates CDX belt (visible difference)
Brakes None (track) or rim Hydraulic disc
Rear dropout 120mm track 135mm horizontal/sliding
Motor None Bafang G020 (stealth hub)

The cutout + belt drive + disc brakes together give the Omera a completely different silhouette from the Detroit while keeping the same aggressive 74°/76° pursuit geometry. Someone who knows bikes would clock it immediately as its own thing. ppl-ai-file-upload.s3.amazonaws

Design Consideration for the Cutout

One thing to flag for the frame builder — the Omera has 135mm rear spacing (not 120mm track), so the seat tube cutout needs to be wider than a typical track frame cutout. The wheel sits in the same plane but the hub flanges and disc rotor are wider. Make sure the cutout clears:

  • Tire (700×25c) + 3mm each side minimum
  • Disc rotor on the non-drive side
  • Belt on the drive side

This is doable but the frame builder needs to know upfront. Want me to add this to the frame fabrication brief?

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eonist commented Mar 12, 2026

okay so you sanwitch the dropout module to chain stay and seat stay and lock it with screwbolts. unscrew the bolts. the gap for belt is there

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eonist commented Mar 12, 2026

omera_split_dropout

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eonist commented Mar 13, 2026

Got it — then we just mirror the function, not the look.

On the non‑drive side:

  • Same axle slot height and length as drive side, so tensioning and wheel position behave identically.
  • One solid 6 mm plate (no split), with: axle slot, brake mount (if rotor that side), and a small hole/feature for hose exit if needed. bikecad
  • Overall 135 mm O.L.D. preserved by making this plate the same thickness as the inner plate on the drive side, so dish stays simple and hub sits centered. alibaba

If you like, I can now define just the critical numbers you need to send your machinist for that non‑drive plate (slot position, thickness, axle center to stay junction, etc.) in plain text.

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